This invention relates to an area infrared receiver, and in particular to an area receiver with antenna-coupled infrared sensors, which include two sets of parallel antenna arms disposed across contact pads and separated from the adjacent arms by bolometers and allows development of area reception from antenna-coupled infrared sensors which are the component pixels for focal-plane arrays of antenna-coupled infrared sensors and this work was supported by Space and Air Warfare Systems Command Contract No. N66001-98-D-6003, and this invention is a Continuation-In-Part of U.S. application Ser. No. 09/004,132 filed on Jan. 7, 1998, now issued as U.S. Pat. No. 6,037,590, which claims the benefit of priority to U.S. Provisional Application No. 60/048,334 filed May 30, 1997, all by the same assignee as the subject invention and which are incorporated by reference.
Infrared (IR) systems have been widely used in the past. Current systems generally require bulk optical systems having multiple moving parts for polarization control. Image forming radiation is typically collected for a fixed polarization state. Optical filters must be used in the optical train before the receiving detector array. The typical weight of the necessary filter and switching assemblies is on the order of 1 kg or more. Polarization-resolved imagery is largely unexploited because of inconvenient implementation, inadequate antenna collectivity and/or receptivity.
Many U.S. Patents have been proposed for infrared detectors but have many of the problems previously described including the preferenced inadequacy of the antenna systems. Arrays of infrared sensors are known: see for example U.S. Pat. No.: 5,021,663 to Hornbeck; U.S. Pat. No. 5,286,976 to Cole; U.S. Pat. No. 5,300,915 to Higashi, et al; U.S. Pat. No. 5,367,167 to Keenan; U.S. Pat. No. 5,591,959 to Cigna, et al; U.S. Pat. No. 5,647,956 to Belcher, et al; and, U.S. Pat. No. 5,436,453 to Chang et al but nowhere is there a mention of antenna-coupled sensors.
Blackwell, et al in U.S. Pat. No. 5,760,398 mentions an antenna (see col. 4, lines 18 and 67; col. 20, line 64 and col. 22, line 1) with respect to absorbtion of incident radiation but only in reference to the primary focus of their disclosure, i.e., the area receiver pixel radiation collector which is geometrical optical based. There is no mention of the dimension of the legs xe2x80x9c1xe2x80x9d that would be required in order to make the connections seen in FIG. 3 into an antenna. The patent talks about the dimensions compared to the wavelength of the reflector 11 and 12 (see col. 9, lines 40-50) but not the antenna arm length in wavelength units. The plural units of FIG. 9 are individual pixels with one sensor per pixel (see col. 6, lines 53-54 and col. 21, line 17) to achieve the desired geometric design and in no way related to cooperate with the legs to provide an area receiver.
Gooch in U.S. Pat. No. 5,777,328 discloses bolometer arrays with no antennas and each bolometer xe2x80x9ca separately sensed pixelxe2x80x9d (see col. 15, line 32).
Silver, et al in U.S. Pat. No. 5,777,336 discloses an array of microcalorimeters responsive to x-ray fluoresence, not infrared radiation.
The first objective of the present invention is to provide an area receiver for an infrared (IR) detector antenna system.
The second object of this invention is to provide an area IR detector antenna system of a plurality of pixels in the form of antenna-coupled IR sensors.
The third object of this invention is to provide an IR detector area antenna system where antenna-coupled IR sensors provide the individual pixels of focal-plane arrays of antenna-coupled IR sensors.
In the subject invention, an infrared (IR) detector antenna for detecting IR radiation has been realized by a pixel array, preferably a focal plane pixel array, of a plurality of infrared (IR) bolometer sensors for receiving IR radiation with a first and a second parallel antenna arm extending outwardly and separately from each of said sensors to parallel contact pads; and output means for receiving the output from said sensors whereby the IR detector antenna unit has enhanced spatial response, fast response and collection efficiency of the IR sensors. Each novel detector pixel can have exterior dimensions of between approximately 10 micrometers to approximately 50 micrometers on each side. The size of the array can be approximately 512 to approximately 2000 micrometers across each side.
These antenna-coupled pixels and their arrays can be used in remote-sensing systems to facilitate IR collection efficiency, enhanced image recognition, feature extraction, and image-clutter removal. The application areas can include earth-resource mapping, pollution monitoring and general surveillance.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.